How to Repair a Backup Generator

Although a generator only needs one spark plug, when it becomes worn or damaged, it must be replaced. Otherwise, your generator will fail to start, or at minimum begin to sputter while it is running. Spark plugs can also crack under pressure in some cases. It is worth your while to periodically inspect the condition of the spark plug. That way, your backup generator will likely be ready to use when you need it.

Things You'll Need

• Wire brush
• Clean cloth
• New spark plug recommended for your backup generator model, if required
• Spark plug gauge (Wire feeler gauge)
• Spark plug socket wrench, 13/16 inch
• Spark plug washer, if required

Instructions

1. Turn off the backup generator and let it cool down for at least 30 minutes.

2. Set the machine on a flat surface, such as a driveway or garage floor.

3. Use your hand to pull off the cap on the spark plug. Take a clean cloth and wipe away all of the dirt and grime from the base.

4. Use the wrench and turn the spark plug counterclockwise to loosen it and then pull it out of its spark plug housing. Go to step 5 if the spark plug is burnt or cracked; skip to step 6 if it is in good condition.

5. Replace the spark plug. Reset the correct gap on the new spark plug using the spark plug gauge (wire feeler gauge). Refer to your backup generator manufacturer's user manual to find the recommended setting. Go to step 7.

6. Scrape the spark plug metal connector 10 times with the wire brush to clean it.

7. Replace the spark plug washer (located between the spark plug and the base of the spark plug housing inside the generator) if it is damaged; otherwise reinstall it.

8. Place the spark plug back in its housing inside the backup generator and then hand-tighten the spark plug to prevent stripping its threads.

9. Compress the washer after you install the spark plug. If the plug is new, tighten it by turning it only 1/2 of a turn. If the plug is used, tighten it by turning it between 1/8 and 1/4 of a turn.